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Are water and conflict linked and what actually links them?
The Water, Peace and Security partnership studies the pathways between water and conflict and the intervening factors. Based on this, it also advices relevant stakeholders to take appropriate action to prevent the deterioration of such situations. It does so by providing a comprehensive package of tools and knowledge that allow for global level analyses of potential water-related conflict hotspots and in-depth local analyses of those, for raising awareness among policy makers on required actions and for advice on which options are available to come to agreed action that can address both the natural and the socio-political aspects of the threat and thus ensure security, peace and sustainable development.
Rigorous test of the performance of shear-wave velocity correlations derived from CPT soundings : a case study for Groningen, the Netherlands
An improved correlation between shear-wave velocity Vs and cone penetration test (CPT) parameters was derived for the Groningen region, the Netherlands, using a set of 154 pairs of CPTs and seismic CPTs. An analysis of a high-quality subset showed that the subdivision into Holocene versus Pleistocene intervals or into cohesive versus non-cohesive intervals did not significantly improve correlation, nor did filtering out of the transition intervals between clay and sand in the non-cohesive dataset. In addition, using qt or qc resulted in similar regression results. We therefore propose a single new equation and we applied this to all available CPTs in the region. The analysis of the fitting bias showed that there is a trend relative to the measured VS. We therefore recommend performing SCPT measurements when very soft soils are encountered, rather than relying on the empirical correlation based on CPT parameters. The comparison of the Vs30 values from CPTs to the model Vs30 of Groningen shows that correlation is excellent: 90% of the calculated Vs30 values from the CPTs fall within one standard deviation of the VS30 of the corresponding geological zone of the model. Although the resulting CPT-VS correlation is specific for the Groningen region, the approach can be applied to other regions with a paired SCPT-CPT dataset.
Sensitivity of storm response to antecedent topography in the XBeach model
Antecedent topography is an important aspect of coastal morphology when studying and forecasting coastal change hazards. The uncertainty in morphologic response of storm-impact models and their use in short-term hazard forecasting and decadal forecasting is important to account for when considering a coupled model framework. This study provided a methodology to investigate uncertainty of profile response within the storm impact model XBeach related to varying antecedent topographies. A parameterized island Gaussian fit (PIGF) model generated an idealized baseline profile and a suite of idealized profiles that vary specific characteristics based on collated observed LiDAR data from Dauphin Island, AL, USA. Six synthetic storm scenarios were simulated on each of the idealized profiles with XBeach in both 1- and 2-dimensional setups and analyzed to determine the morphological response and uncertainty related to the varied antecedent topographies. Profile morphologic response tends to scale with storm magnitude but among the varied profiles there is greater uncertainty in profile response to the medium range storm scenarios than to the low and high magnitude storm scenarios. XBeach can be highly sensitive to morphologic thresholds, both antecedent and time-varying, especially with regards to beach slope.
A CNN-LSTM method for the morphology evolution prediction of beach mega-nourishment
Sand nourishment is widely adopted as an effective soft approach to provide long-term coastal safety, protect the ecology environment, and promote tourism and recreation. With the increase in frequency and expenses in beach nourishment worldwide, an adequate prediction of morphology evolution is greatly desired for coastline management. Based on detailed monitoring data of the mega-nourishment Sand Engine, this article integrates a convolutional neural network (CNN) and long short-term memory (LSTM) to predict the nourishment morphology evolution. The historical surveyed data are transformed into sequence grids, which are input into the CNN to obtain the spatial features of beach nourishment. The CNN is constructed by performing the convolutional and pooling operation on the historical data, which can extract actual spatial features and reduce network complexity. The output of the CNN is input to LSTM to learn the temporal relationship to predict future nourishment terrain using past time-series features. Finally, the LSTM output is decoded by the fully connected layer to obtain the prediction result. The complex spatiotemporal correlations among the input data are identied through effective training of the proposed model. The major contribution of this article is to propose a data-driven model that combines CNN and LSTM for the morphology evolution prediction of beach nourishment, and validate the effectiveness of the proposed model by comparing with the performances of other popular methods in predicting the nourishment changes.
Sediment morphology and the flow velocity field in a gully pot : an experimental study
Urban runoff (re)mobilises solids present on the street surface and transport them to urban drainage systems. The solids reduce the hydraulic capacity of the drainage system due to sedimentation and on the quality of receiving water bodies due to discharges via outfalls and combined sewer overflows (CSOs) of solids and associated pollutants. To reduce these impacts, gully pots, the entry points of the drainage system, are typically equipped with a sand trap, which acts as a small settling tank to remove suspended solids. This study presents data obtained using Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) measurements in a scale 1:1 gully to quantify the relation between parameters such as the gully pot geometry, discharge, sand trap depth, and sediment bed level on the flow field and subsequently the settling and erosion processes. The results show that the dynamics of the morphology of the sediment bed influences the flow pattern and the removal effciency in a significant manner, prohibiting the conceptualization of a gully pot as a completely mixed reactor. Resuspension is initiated by the combination of both high turbulent fluctuations and high mean flow, which is present when a substantial bed level is present. In case of low bed levels, the overlaying water protects the sediment bed from erosion.
A dataset on trophic modes of aquatic protists
Due to the historical dichotomy, it is not straightforward to gain adequate and correct information on the trophic mode of aquatic protists. Long hours of literature research or expert knowledge are needed to correctly assign trophic modes. Additionally, aquatic protists also have a long history of undergoing taxonomic changes which make it difficult to compare past and present literature. While WoRMS, the World Register of Marine Species, keeps track of the taxonomic changes and assigns each species a unique AphiaID that can be linked to its various historic and present taxonomic hierarchy, there is currently no machine-readable database to query aquatic protists for their trophic modes. This paper describes a dataset that was submitted to WoRMS and links aquatic protist taxa, with a focus on marine taxa, to their AphiaID and their trophic mode. The bulk of the data used for this dataset stems from (routine) monitoring stations in the North Sea and the Baltic Sea. The data were augmented and checked against state-of-the-art knowledge on mixoplankton taxa by consulting literature and experts. Thus, this dataset provides a first attempt to make the trophic mode of aquatic protists easily accessible in both a human- and machine-readable format.
The influence of apparatus stiffness on the results of cyclic direct simple shear tests on dense sand
A series of undrained cyclic direct simple shear (CDSS) tests on dense Toyoura sand has been performed with the aim to investigate the influence of the stiffness of the DSS device on test results. To this end, springs were installed to reduce deliberately the stiffness of the apparatus. It is shown that the cyclic resistance of the sand depends strongly on the rigidity of the apparatus frame. In particular, as the stiffness of the DSS device increases, the number of loading cycles required to reach liquefaction decreases. This pronounced apparatus–stiffness dependence is of great practical concern in geotechnical engineering because it directly implies that the CDSS response of a soil sample can be predominantly controlled by the stiffness of the apparatus and not by the soil behavior alone. In addition, the test results indicate that the effect of equipment compliance in cyclic undrained DSS testing can be minimized when the ratio of the stiffness of the tested sand sample to the stiffness of the apparatus has a significantly low value.
Zonne-atollen geven ruimte aan natuur en duurzame energie : een verkenning
Dit project verkent of de doelen van het project Wieringerhoek te koppelen zijn met energie doelen in de regio Noord-Holland Noord. De centrale vraag is of er een variant te ontwerpen en in te richten is waarin én duurzame energie wordt opgewekt én waarin natuurwaarden een kwaliteitsimpuls krijgen zoals beoogd voor het PAGW project Wieringerhoek. Dit rapport beschrijft een variant waarvan wij denken dat er sprake is van een substantiële koppeling van deze doelen en dus van meervoudig ruimtegebruik. Deze variant komt daarom in aanmerking om meegewogen te worden in de MER procedure van het PAGW project Wieringerhoek. Deze korte verkenning laat zien dat het opwaarderen van natuur goed samen kan gaan met ruimte creëren voor de opwekking van duurzame energie middels zonnepanelen op water. Het aanleggen van zonne-atollen ofwel ringdijken met open verbinding met het meer resulteert in een water oppervlak waar golfwerking sterk gereduceerd is zodat zonnepanelen veilig geplaatst kunnen worden. In deze verkenning hebben we gekozen voor een bedekkingspercentage met panelen van 50% van het oppervlak. Als de bodem onder de zonnepanelen – binnen de zonne-atollen - opgehoogd wordt of wel verondiept met lokaal sediment kan het licht doordringen tot aan de bodem. Hierdoor wordt een gunstige omgeving gecreëerd voor waterplanten en natuurlijk ook voor vis en macrofauna zoals mosselen. Een mooi voorbeeld van meervoudig ruimtegebruik waarbij de PAGW opgave qua ruimtebeslag benut wordt voor de functie opwekking duurzame energie.
Modelonzekerheidsfactoren Spencer-Van der Meij model en ongedraineerde schuifsterkte
Voor de beoordeling van macrostabiliteit binnenwaarts bij dijken worden glijvlakmodellen gebruikt. Dit rapport adviseert over de modelonzekerheid (gemiddelde, standaardafwijking, en partiële veiligheidsfactor) bij het gebruik van glijvlakmodellen Spencer-Van der Meij, Uplift-Van en Bishop in stabiliteitsanalyses met ongedraineerde schuifsterkte binnen het WTI 2017. Hiervoor zijn beschouwd: het vereiste betrouwbaarheidsniveau, de effecten van automatisch positioneren van het zoekgebied, en empirische observaties. Door de modelfactor te relateren aan empirische observaties wordt zowel de onzekerheid over het schuifvlakmodel als de onzekerheid over de modellering van de schuifsterkte in de modelfactor verdisconteerd.
Eindrapportage monitoring- en onderzoeksprogramma natuurcompensatie Voordelta (PMR-NCV)
In 2006 is een planologische kernbeslissing genomen over het Project Mainportontwikkeling Rotterdam (PMR). In dit kader is in 2008 begonnen met de aanleg van Maasvlakte 2. In samenhang daarmee zijn natuurcompensatiemaatregelen genomen in de Voordelta. Vanaf 2009 is in het kader van het project Natuurcompensatie Voordelta (PMR-NCV) een monitoring- en onderzoeksprogramma uitgevoerd in de Voordelta, voortvloeiend uit de monitoringverplichtingen in het kader van de vergunning op grond van de Nb-wet 1998 voor de aanleg en aanwezigheid van Maasvlakte 2 en de bijbehorende natuurcompensatie. Dit rapport vormt de wetenschappelijke rapportage over de resultaten van het programma. Het rapport geeft een synthese van de monitorings- en onderzoeksresultaten uit de nulmetingen (2004-2007) en de eerste (2009-2015) en tweede (2016-2018) fase van PMR-NCV, aangevuld met de resultaten van ander relevant onderzoek. Op grond hiervan worden de effecten van de natuurcompensatiemaatregelen beschreven. Dit rapport vormt een vervolg op de in 2018 gepubliceerde synthese (Tulp et al., 2018a). Het rapport omvat zowel een actualisatie van analyseresultaten en conclusies op basis van meetgegevens uit recente jaren die nog niet beschikbaar waren in 2018, als resultaten van nieuwe analyses. Vanwege de grote onderzoeksinspanning die verricht is, zou het te ver voeren om in dit rapport een volledig overzicht te geven van alle onderzoeks- en monitoringsresultaten. Het rapport beperkt zich tot de belangrijkste resultaten met het oog op beantwoorden van de vragen over de effecten van de natuurcompensatie.